A cancer-associated mutation in H2A.Z decreases nucleosome stability and impairs mitotic progression

The histone variant H2A.Z is one of the most evolutionally conserved histone variants. Here, we identified a cancer-associated mutation in H2A.Z and evaluate the mutation. Structural and biochemical in vitro analyses showed that the H2A.Z mutation destabilizes nucleosome containing it. Then we applied the genetic complementation analysis to analyze cellular functions of the H2A.Z mutant. Although the H2A.Z mutant is deposited into nucleosome and rescues the lethality of H2A.Z DKO cells, the mutant does not complement mitotic defects of H2A.Z DKO cells, suggesting that stability of H2A.Z nucleosome is required for proper mitotic progression. Importantly, the H2A.Z mutant led to mitotic defects even in the presence of a larger pool of wild-type H2A.Z. Thus, it is implicated that the cancer-associated mutation appeared in an allele of the H2A.Z isoform genes would be involved in carcinogenesis through causing mitotic defects. DT40 H2A.Z DKO cells stably expressing exogenous H2A.Z.1 or its mutant (H2A.Z-R80C) were cultured in the DMEM medium without tetracycline. Total RNAs were extracted with the RNeasy mini kit (QIAGEN) according to the manufacturer's protocol. 100 ng of total RNAs was processed for microarray by using the Agilent expression array (Agilent).